Tough run ...

This morning, I did the 12th workout of the PowerBar Intermediate Marathon Program (targeted at the Baltimore Marathon), a "1:30 easy run." I picked one of my 10-mile routes (actually, 9.83 according to my new GPS watch), which, since last fall, I've been running in the low 1:30's, usually with one water stop but sometimes nonstop. Today's was not one of those; today I took five water stops, and I needed--or, at least I thought I needed--every one of them. It felt different today. And, of course, I spent the rest of the day going through in my mind the whys. The obvious would be the heat (mid to upper 80s) and not yet being acclimatized. Another would be last Wednesday evening's track workout from which I might not have fully recovered. But, it's the thought of age catching up that nags. The decline in potential in long distance running is supposed to be very gradual, and I've at least a number of years to go before the potential declines to that of someone in the late teens. And, of course, depending on how one trains, the adaptation curve could be kept above the aging curve beyond the average. That nagging feeling lingered, until I took a look at the past dates that I've run this route. That's when I smiled. All the runs in the low 1:30's occurred in the fall, winter, or spring. The slower ones, including today's, were all in the summer. Ergo, it must have been the heat!